Conventionally, a combination weigher is used to combine objects which are non-uniform in weights to efficiently attain a target weight.
This combination weigher typically includes a dispersion feeder which is capable of dispersing and supplying the objects evenly to components around the dispersion feeder, a plurality of linear feeders arranged at equal intervals around the dispersion feeder, feeding hoppers arranged so as to correspond to the linear feeders, respectively, and weighing hoppers arranged so as to correspond to the linear feeders, respectively.
In the above configuration, the objects are sent from the dispersion feeder to linear troughs of the linear feeders, and the objects of a suitable amount are transported by vibration on the linear troughs by vibration components of the linear feeders and fed to the weighing hoppers coupled to load cells through the feeding hoppers, respectively. The load cells detect weights of the objects inside of the weighing hoppers. Based on a combination of weight values of the weighing hoppers, the weighing hoppers making up an optimal combination in which the weight of the objects falls within a target weight of the objects, are selected. Then, the objects are discharged from the weighing hoppers selected to make up the combination collectively onto a collecting chute located therebelow. A packaging machine packages the collective objects.
In the combination weigher as described above, each of the feeding hopper and the weighing hopper includes a hopper body and a hopper gate. The hopper gate is applied with a load (impact) in a direction to open the hopper gate by a gravitational force of the objects when the objects are fed from a previous unit (linear feeder in the case of the feeding hopper, the feeding hopper in the case of the weighing hopper). Therefore, typically, a stopper section and the like are provided to prevent the hopper gate from being opened by mistake.
For example, Patent Literature 1 discloses a mechanism for opening and closing a hopper gate including a stopper section which is able to inhibit the hopper gate from being opened by restricting a rotation of a support bracket coupled to a hopper unit (e.g., see FIG. 4 in Patent Literature 2). This stopper section is disposed inside of an actuator unit (hopper unit).
By comparison, Patent Literature 2 discloses a mechanism for opening and closing a hopper gate including a toggle link mechanism which is able to inhibit a gate of a hopper from being opened (e.g., see FIG. 7 in Patent Literature 1). The toggle link mechanism is known as a means for effectively holding the hopper gate to prevent the hopper gate from being opened. In particular, since the toggle link mechanism is attached on the hopper body in the example of Patent Literature 2, the interior of the actuator unit can be configured as a simple mechanism.